// Command mciasgrpcctl is the MCIAS gRPC admin CLI.
//
// It connects to a running mciassrv gRPC listener and provides subcommands for
// managing accounts, roles, tokens, and Postgres credentials via the gRPC API.
//
// Usage:
//
//	mciasgrpcctl [global flags] <command> [args]
//
// Global flags:
//
//	-server  gRPC server address (default: localhost:9443)
//	-token   Bearer token for authentication (or set MCIAS_TOKEN env var)
//	-cacert  Path to CA certificate for TLS verification (optional)
//
// Commands:
//
//	health
//	pubkey
//
//	account list
//	account create -username NAME -password PASS [-type human|system]
//	account get    -id UUID
//	account update -id UUID -status active|inactive
//	account delete -id UUID
//
//	role list  -id UUID
//	role set   -id UUID -roles role1,role2,...
//
//	token validate -token TOKEN
//	token issue    -id UUID
//	token revoke   -jti JTI
//
//	pgcreds get -id UUID
//	pgcreds set -id UUID -host HOST [-port PORT] -db DB -user USER -password PASS
package main

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"encoding/json"
	"flag"
	"fmt"
	"os"
	"strings"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
	"google.golang.org/grpc/metadata"

	mciasv1 "git.wntrmute.dev/kyle/mcias/gen/mcias/v1"
)

func main() {
	// Global flags.
	serverAddr := flag.String("server", "localhost:9443", "gRPC server address (host:port)")
	tokenFlag := flag.String("token", "", "bearer token (or set MCIAS_TOKEN)")
	caCert := flag.String("cacert", "", "path to CA certificate for TLS")
	flag.Usage = usage
	flag.Parse()

	// Resolve token from flag or environment.
	bearerToken := *tokenFlag
	if bearerToken == "" {
		bearerToken = os.Getenv("MCIAS_TOKEN")
	}

	args := flag.Args()
	if len(args) == 0 {
		usage()
		os.Exit(1)
	}

	// Build gRPC connection.
	conn, err := newGRPCConn(*serverAddr, *caCert)
	if err != nil {
		fatalf("connect to gRPC server: %v", err)
	}
	defer func() { _ = conn.Close() }()

	ctl := &controller{
		conn:  conn,
		token: bearerToken,
	}

	command := args[0]
	subArgs := args[1:]

	switch command {
	case "health":
		ctl.runHealth()
	case "pubkey":
		ctl.runPubKey()
	case "account":
		ctl.runAccount(subArgs)
	case "role":
		ctl.runRole(subArgs)
	case "token":
		ctl.runToken(subArgs)
	case "pgcreds":
		ctl.runPGCreds(subArgs)
	default:
		fatalf("unknown command %q; run with no args to see usage", command)
	}
}

// controller holds the shared gRPC connection and token for all subcommands.
type controller struct {
	conn  *grpc.ClientConn
	token string
}

// authCtx returns a context with the Bearer token injected as gRPC metadata.
// Security: token is placed in the "authorization" key per the gRPC convention
// that mirrors the HTTP Authorization header. Value is never logged.
func (c *controller) authCtx() context.Context {
	ctx := context.Background()
	if c.token == "" {
		return ctx
	}
	// Security: metadata key "authorization" matches the server-side
	// extractBearerFromMD expectation; value is "Bearer <token>".
	return metadata.AppendToOutgoingContext(ctx, "authorization", "Bearer "+c.token)
}

// callCtx returns an authCtx with a 30-second deadline.
func (c *controller) callCtx() (context.Context, context.CancelFunc) {
	return context.WithTimeout(c.authCtx(), 30*time.Second)
}

// ---- health / pubkey ----

func (c *controller) runHealth() {
	adminCl := mciasv1.NewAdminServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := adminCl.Health(ctx, &mciasv1.HealthRequest{})
	if err != nil {
		fatalf("health: %v", err)
	}
	printJSON(map[string]string{"status": resp.Status})
}

func (c *controller) runPubKey() {
	adminCl := mciasv1.NewAdminServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := adminCl.GetPublicKey(ctx, &mciasv1.GetPublicKeyRequest{})
	if err != nil {
		fatalf("pubkey: %v", err)
	}
	printJSON(map[string]string{
		"kty": resp.Kty,
		"crv": resp.Crv,
		"use": resp.Use,
		"alg": resp.Alg,
		"x":   resp.X,
	})
}

// ---- account subcommands ----

func (c *controller) runAccount(args []string) {
	if len(args) == 0 {
		fatalf("account requires a subcommand: list, create, get, update, delete")
	}
	switch args[0] {
	case "list":
		c.accountList()
	case "create":
		c.accountCreate(args[1:])
	case "get":
		c.accountGet(args[1:])
	case "update":
		c.accountUpdate(args[1:])
	case "delete":
		c.accountDelete(args[1:])
	default:
		fatalf("unknown account subcommand %q", args[0])
	}
}

func (c *controller) accountList() {
	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.ListAccounts(ctx, &mciasv1.ListAccountsRequest{})
	if err != nil {
		fatalf("account list: %v", err)
	}
	printJSON(resp.Accounts)
}

func (c *controller) accountCreate(args []string) {
	fs := flag.NewFlagSet("account create", flag.ExitOnError)
	username := fs.String("username", "", "username (required)")
	password := fs.String("password", "", "password (required for human accounts)")
	accountType := fs.String("type", "human", "account type: human or system")
	_ = fs.Parse(args)

	if *username == "" {
		fatalf("account create: -username is required")
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.CreateAccount(ctx, &mciasv1.CreateAccountRequest{
		Username:    *username,
		Password:    *password,
		AccountType: *accountType,
	})
	if err != nil {
		fatalf("account create: %v", err)
	}
	printJSON(resp.Account)
}

func (c *controller) accountGet(args []string) {
	fs := flag.NewFlagSet("account get", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("account get: -id is required")
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.GetAccount(ctx, &mciasv1.GetAccountRequest{Id: *id})
	if err != nil {
		fatalf("account get: %v", err)
	}
	printJSON(resp.Account)
}

func (c *controller) accountUpdate(args []string) {
	fs := flag.NewFlagSet("account update", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	status := fs.String("status", "", "new status: active or inactive (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("account update: -id is required")
	}
	if *status == "" {
		fatalf("account update: -status is required")
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	_, err := cl.UpdateAccount(ctx, &mciasv1.UpdateAccountRequest{
		Id:     *id,
		Status: *status,
	})
	if err != nil {
		fatalf("account update: %v", err)
	}
	fmt.Println("account updated")
}

func (c *controller) accountDelete(args []string) {
	fs := flag.NewFlagSet("account delete", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("account delete: -id is required")
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	_, err := cl.DeleteAccount(ctx, &mciasv1.DeleteAccountRequest{Id: *id})
	if err != nil {
		fatalf("account delete: %v", err)
	}
	fmt.Println("account deleted")
}

// ---- role subcommands ----

func (c *controller) runRole(args []string) {
	if len(args) == 0 {
		fatalf("role requires a subcommand: list, set")
	}
	switch args[0] {
	case "list":
		c.roleList(args[1:])
	case "set":
		c.roleSet(args[1:])
	default:
		fatalf("unknown role subcommand %q", args[0])
	}
}

func (c *controller) roleList(args []string) {
	fs := flag.NewFlagSet("role list", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("role list: -id is required")
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.GetRoles(ctx, &mciasv1.GetRolesRequest{Id: *id})
	if err != nil {
		fatalf("role list: %v", err)
	}
	printJSON(resp.Roles)
}

func (c *controller) roleSet(args []string) {
	fs := flag.NewFlagSet("role set", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	rolesFlag := fs.String("roles", "", "comma-separated list of roles")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("role set: -id is required")
	}

	var roles []string
	if *rolesFlag != "" {
		for _, r := range strings.Split(*rolesFlag, ",") {
			r = strings.TrimSpace(r)
			if r != "" {
				roles = append(roles, r)
			}
		}
	}

	cl := mciasv1.NewAccountServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	_, err := cl.SetRoles(ctx, &mciasv1.SetRolesRequest{Id: *id, Roles: roles})
	if err != nil {
		fatalf("role set: %v", err)
	}
	fmt.Printf("roles set: %v\n", roles)
}

// ---- token subcommands ----

func (c *controller) runToken(args []string) {
	if len(args) == 0 {
		fatalf("token requires a subcommand: validate, issue, revoke")
	}
	switch args[0] {
	case "validate":
		c.tokenValidate(args[1:])
	case "issue":
		c.tokenIssue(args[1:])
	case "revoke":
		c.tokenRevoke(args[1:])
	default:
		fatalf("unknown token subcommand %q", args[0])
	}
}

func (c *controller) tokenValidate(args []string) {
	fs := flag.NewFlagSet("token validate", flag.ExitOnError)
	tok := fs.String("token", "", "JWT to validate (required)")
	_ = fs.Parse(args)

	if *tok == "" {
		fatalf("token validate: -token is required")
	}

	cl := mciasv1.NewTokenServiceClient(c.conn)
	// ValidateToken is public — no auth context needed.
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := cl.ValidateToken(ctx, &mciasv1.ValidateTokenRequest{Token: *tok})
	if err != nil {
		fatalf("token validate: %v", err)
	}
	printJSON(map[string]interface{}{
		"valid":   resp.Valid,
		"subject": resp.Subject,
		"roles":   resp.Roles,
	})
}

func (c *controller) tokenIssue(args []string) {
	fs := flag.NewFlagSet("token issue", flag.ExitOnError)
	id := fs.String("id", "", "system account UUID (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("token issue: -id is required")
	}

	cl := mciasv1.NewTokenServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.IssueServiceToken(ctx, &mciasv1.IssueServiceTokenRequest{AccountId: *id})
	if err != nil {
		fatalf("token issue: %v", err)
	}
	printJSON(map[string]string{"token": resp.Token})
}

func (c *controller) tokenRevoke(args []string) {
	fs := flag.NewFlagSet("token revoke", flag.ExitOnError)
	jti := fs.String("jti", "", "JTI of the token to revoke (required)")
	_ = fs.Parse(args)

	if *jti == "" {
		fatalf("token revoke: -jti is required")
	}

	cl := mciasv1.NewTokenServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	_, err := cl.RevokeToken(ctx, &mciasv1.RevokeTokenRequest{Jti: *jti})
	if err != nil {
		fatalf("token revoke: %v", err)
	}
	fmt.Println("token revoked")
}

// ---- pgcreds subcommands ----

func (c *controller) runPGCreds(args []string) {
	if len(args) == 0 {
		fatalf("pgcreds requires a subcommand: get, set")
	}
	switch args[0] {
	case "get":
		c.pgCredsGet(args[1:])
	case "set":
		c.pgCredsSet(args[1:])
	default:
		fatalf("unknown pgcreds subcommand %q", args[0])
	}
}

func (c *controller) pgCredsGet(args []string) {
	fs := flag.NewFlagSet("pgcreds get", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	_ = fs.Parse(args)

	if *id == "" {
		fatalf("pgcreds get: -id is required")
	}

	cl := mciasv1.NewCredentialServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	resp, err := cl.GetPGCreds(ctx, &mciasv1.GetPGCredsRequest{Id: *id})
	if err != nil {
		fatalf("pgcreds get: %v", err)
	}
	if resp.Creds == nil {
		fatalf("pgcreds get: no credentials returned")
	}
	printJSON(map[string]interface{}{
		"host":     resp.Creds.Host,
		"port":     resp.Creds.Port,
		"database": resp.Creds.Database,
		"username": resp.Creds.Username,
		"password": resp.Creds.Password,
	})
}

func (c *controller) pgCredsSet(args []string) {
	fs := flag.NewFlagSet("pgcreds set", flag.ExitOnError)
	id := fs.String("id", "", "account UUID (required)")
	host := fs.String("host", "", "Postgres host (required)")
	port := fs.Int("port", 5432, "Postgres port")
	dbName := fs.String("db", "", "Postgres database name (required)")
	username := fs.String("user", "", "Postgres username (required)")
	password := fs.String("password", "", "Postgres password (required)")
	_ = fs.Parse(args)

	if *id == "" || *host == "" || *dbName == "" || *username == "" || *password == "" {
		fatalf("pgcreds set: -id, -host, -db, -user, and -password are required")
	}

	cl := mciasv1.NewCredentialServiceClient(c.conn)
	ctx, cancel := c.callCtx()
	defer cancel()

	_, err := cl.SetPGCreds(ctx, &mciasv1.SetPGCredsRequest{
		Id: *id,
		Creds: &mciasv1.PGCreds{
			Host:     *host,
			Port:     int32(*port), //nolint:gosec // G115: port validated as [1,65535] by flag parsing
			Database: *dbName,
			Username: *username,
			Password: *password,
		},
	})
	if err != nil {
		fatalf("pgcreds set: %v", err)
	}
	fmt.Println("credentials stored")
}

// ---- gRPC connection ----

// newGRPCConn dials the gRPC server with TLS.
// If caCertPath is empty, the system CA pool is used.
// Security: TLS 1.2+ is enforced by the crypto/tls defaults on the client side.
// The connection is insecure-skip-verify-free; operators can supply a custom CA
// for self-signed certs without disabling certificate validation.
func newGRPCConn(serverAddr, caCertPath string) (*grpc.ClientConn, error) {
	tlsCfg := &tls.Config{
		MinVersion: tls.VersionTLS12,
	}

	if caCertPath != "" {
		// G304: path comes from a CLI flag supplied by the operator, not
		// from untrusted input. File inclusion is intentional.
		pemData, err := os.ReadFile(caCertPath) //nolint:gosec
		if err != nil {
			return nil, fmt.Errorf("read CA cert: %w", err)
		}
		pool := x509.NewCertPool()
		if !pool.AppendCertsFromPEM(pemData) {
			return nil, fmt.Errorf("no valid certificates found in %s", caCertPath)
		}
		tlsCfg.RootCAs = pool
	}

	creds := credentials.NewTLS(tlsCfg)
	conn, err := grpc.NewClient(serverAddr, grpc.WithTransportCredentials(creds))
	if err != nil {
		return nil, fmt.Errorf("dial %s: %w", serverAddr, err)
	}
	return conn, nil
}

// ---- helpers ----

// printJSON pretty-prints a value as JSON to stdout.
func printJSON(v interface{}) {
	enc := json.NewEncoder(os.Stdout)
	enc.SetIndent("", "  ")
	if err := enc.Encode(v); err != nil {
		fatalf("encode output: %v", err)
	}
}

// fatalf prints an error message to stderr and exits with code 1.
func fatalf(format string, args ...interface{}) {
	fmt.Fprintf(os.Stderr, "mciasgrpcctl: "+format+"\n", args...)
	os.Exit(1)
}

func usage() {
	fmt.Fprintf(os.Stderr, `mciasgrpcctl - MCIAS gRPC admin CLI

Usage: mciasgrpcctl [global flags] <command> [args]

Global flags:
  -server  gRPC server address (default: localhost:9443)
  -token   Bearer token (or set MCIAS_TOKEN env var)
  -cacert  Path to CA certificate for TLS verification

Commands:
  health
  pubkey

  account list
  account create  -username NAME -password PASS [-type human|system]
  account get     -id UUID
  account update  -id UUID -status active|inactive
  account delete  -id UUID

  role list  -id UUID
  role set   -id UUID -roles role1,role2,...

  token validate  -token TOKEN
  token issue     -id UUID
  token revoke    -jti JTI

  pgcreds get  -id UUID
  pgcreds set  -id UUID -host HOST [-port PORT] -db DB -user USER -password PASS
`)
}